To deny something is to say something is not true, or say that you DID NOT do something: The teenager denied stealing the DVDs from the store. The businessman denied the accusations that he had stolen money from the company. (He said he didn't do it)
To refuse is NOT to do something, or to say firmly that you WILL NOT do something: My 5-year-old son is refusing to go to bed because he wants to keep playing with his toys. The employee was fired after he refused to do what the manager asked.
Note that after deny we use the -ing form or a noun, and after refuse we use the "to" form of the verb.
To reject something is to not accept it - often because it's not good enough, or because you don't believe in it. She was rejected from the state university because her grades were terrible. Gary is an atheist. He rejects the idea of god. He asked her out to dinner, but she rejected him.
To decline is to say "no" politely to a proposal, invitation, or suggestion Thank you for your invitation to the banquet, but I'm afraid I'll have to decline. The president declined to comment on the political scandal.
The Power behind the Engine
A very simple illustration of the working of a steam engine is given in Figure. Steam under pressure enters through the opening F
, passes through N
, and presses upon the piston M
. As a result M
moves downward, and thereby induces rotation in the large wheel L
falls it drives the air in D
out through O
(the opening P
is not visible in the diagram).
As soon as this is accomplished, a mechanical device draws up the rod E
, which in turn closes the opening N
, and thus prevents the steam from passing into the part of D
But when the rod E
is in such a position that N
is closed, O
on the other hand is open, and steam rushes through it into D
and forces up the piston. This up-and-down motion of the piston causes continuous rotation of the wheel L
. If the fire is hot, steam is formed quickly, and the piston moves rapidly; if the fire is low, steam is formed slowly, and the piston moves less rapidly.
The steam engine as seen on our railroad trains is very complex, and cannot be discussed here; in principle, however, it is identical with that just described. Figure shows a steam harvester at work on a modern farm.
In both engine and turbine the real source of power is not the steam but the fuel, such as coal or oil, which converts the water into steam.
FIG. - The principle of the steam engine.
FIG. - Steam harvester at work.